轮轨冲击对构架疲劳的影响

Influence of wheel-rail impact on fatigue of bogie frame

以三轴机车转向架构架为例,建立其轮轨冲击的运动微分方程,通过龙格-库塔积分法得到了轮轨冲击的载荷时间历程,分析了轮轨动态冲击对构架疲劳寿命的影响。利用有限单元法建立了轮对、构架、车体的整体有限元模型,采用瞬态动力学分析得到构架危险点的应力时间历程,结合材料的S-N曲线以及疲劳损伤累积准则,进行了构架的疲劳寿命计算,得到轮轨低接头冲击下构架疲劳寿命。分析结果表明:构架的应力响应并不与轮轨处的激励同时达到最大,且在激励结束后有一较长的响应过程;轮轨冲击对构架的疲劳影响较大,尤其对轴箱弹簧座处的侧梁下盖板的寿命影响最为显著,在25·0m轨长的错牙接头作用下,其疲劳寿命为5·15×106km。

In order to analyze the effect of wheel-rail impact on the fatigue life of bogie frame, a bogie frame of a three-axle locomotive was taken as an example, the differential equation of wheel-rail impact was established, and the load history of wheel-rail impact was obtained by using Runge-Kutta formula. A finite element model consisting of wheelsets, bogie frame and carbody was established by using finite element method, the stress histories of different dangerous points on the frame were derived by using transient dynamics analysis technology, the S-N relations of 16Mn material and fatigue damage cumulative rule were analyzed, and the fatigue life of the frame was calculated under the impact of wheel-rail tie-in. Analysis result shows that the stress response of the frame is not accordant with wheel-rail impact force to achieve the maximum value, but there is a longer response process after impacting; the influence of wheel-rail impact on the fatigue of bogie frame is great, especially, on the cover board of side-girder near axle box spring block, and the fatigue life of the frame is 5.15 × 10^6 km under its malocclusion joint for 25.0 m long track. 2 tabs, 10 figs, 10 refs.